Ex post facto
Latin for "from a thing done afterward." Ex post facto is most typically used to refer to a law that applies retroactively, thereby criminalizing conduct that was legal when originally performed. Two clauses in the US Constitution prohibit ex post facto laws: Art 1, § 9 and Art. 1 § 10. see, e.g. Collins v. Youngblood 497 US 37 (1990) and California Dep't of Corrections v. Morales 514 US 499 (1995).
Why are pro-gun attorneys in such short supply?EX POST FACTO CLAUSE - A misnomer in that actually two Constitutional clauses are involved. The U.S. Constitution's Article 1 Section 9, C.3 states: 'No Bill of Attainder or ex post facto Law shall be passed,' and Section 10 says: 'No State shall enter into any Treaty, Alliance, or Confederation; grant Letters of Marque and Reprisal; coin Money; emit Bills of Credit; make any Thing but gold and silver Coin a Tender in Payment of Debts; pass any Bill of Attainder, ex post facto Law. . . .'
The 'words and the intent' of the Ex Post Facto Clause encompass '[e]very law that changes the punishment, and inflicts a greater punishment, than the law annexed to the crime, when committed.' Calder v. Bull, 3 U.S. (1 Dall.) 386, 390 (1798) (opinion of Chase, J.).
An ex post facto law is a law passed after the occurrence of an event or action which retrospectively changes the legal consequences of the event or action.